Not mine but I was in the same room (took place at college). Two brothers were taking similar classes and somehow began arguing about the physics of how a vampire would be invisible in a mirror. To the point where they were yelling at the other brother about his lack of understanding of refractive physics and geology of the minerals that were smelled to make the mirror glass. The debate was whether a vampire would be visible when viewed through soda glass versus lime glass. Eventually I had to break their debate since they were being so loud and aggressive that people thought they were gonna come to bless over it.